This invention pertains to means for forming a fluid seal in a void or recess which obtains between interengaged components, and in particular to such means which forms a static and sanitary seal, in a space, void or recess between such components which fairingly bridges across the space, void or recess to inhibit any collection of fluid thereat.
Typically, sealing means are embodied by an O-ring, used as a radial seal between interengaging components, the O-ring seal serving as a gland, or arranged as a face seal. Alternatively, such sealing means are provided by a flat gasket, in which the same serves as a face seal between the components. In the case where an O-ring is used to achieve a radial seal between interengaged components, it is necessary for the O-ring groove to be machined or formed so that it is somewhat below the outermost surfaces of the components. This is necessary to provide some manner of shoulder to keep the O-ring from extruding into the flow path of the fluid, as the O-ring is compressed, or extruded into the structures as a vacuum is created therewithin. The elastomers used for O-ring materials are flexible enough to extrude outwardly or inwardly, in the face of elevated or vacuum pressures. The distance between the face of the O-ring seal and the outermost surfaces of the interengaged, being-sealed components defines gaps and crevasses which will fill with product upon such product flowing thereacross. These gaps and crevasses are difficult and almost impossible to flush out and sterilize.
As pressures increase or decrease, within the being-sealed components, the O-ring moves back and forth, slightly, as it is compressed and allowed to expand due to the variances in the pressures, because of its highly elastic nature. As a consequence, small amounts of product become trapped in areas around or beneath the O-ring. Clearly, any bacteria that grows near or beneath the O-ring as a result of the entrapped product will be insulated from cleansing steam addressed to the site. Such O-ring sealing arrangements are most difficult or impossible to sanitize for, as noted, sanitizing steam will simply pass over the captured, shielded bacteria.
An O-ring seal used as a face seal also requires a same type of shoulder to retain it in place, and the aforesaid problems arise with this practice as well. Recesses, gaps and the like will be presented to collect fluid therein, and such discontinuities are fertile breeding grounds for tenacious bacteria.
A flat gasket used as a face seal is also subject to extrusion, inwardly or outwardly, under elevated or vacuum pressures due to its highly elastic nature. Also, because a flat gasket has to be compressed against comparatively large, flat surfaces, the use of such results in an arrangement that either has a significant, product-receptive recess at the outermost area of the structure, or defines gaps and crevasses such as are coincident with the O-ring sealing (as priorly noted), compromising the cleanliness and sterility of the arrangement.
In view of the aforenoted problems and disadvantages arising from the use of O-ring seals and/or flat gaskets, it is clear that there is an unmet need for a means for forming a static and sanitary seal which avoids the described problems and disadvantages.